A radio-frequency identification (RFID) system may be used for a number of applications, such as managing inventory, electronic access control, security systems, automatic identification of cars on toll roads, electronic article surveillance (EAS), and so forth. A RFID system may comprise a RFID reader and a RFID device. The RFID reader may transmit a radio-frequency carrier signal to the RFID device. The RFID device may respond to the carrier signal with a data signal encoded with information stored by the RFID device.
A RFID device typically includes an antenna to communicate signals between the RFID device and the RFID reader. The antenna should be tuned to operate within a predetermined operating frequency or range of frequencies. Improved techniques to tune an antenna may increase the performance of an RFID system, as well as reduce associated costs. Accordingly, there may be need for improved tunable antennas in an RFID system.